The LED technology has advantages such as high efficiency, energy saving and long lifetime and is currently widely used in the illumination technology. In an LED illuminating device, a heat dissipating performance is very important and directly affects a normal operation of the LED illuminating device, and especially there is a need to improve a heat dissipation effect between an LED light engine and a housing of the illuminating device. A heat dissipation device manufactured by a die casting process is usually used in, for example, a B- or P-type LED illuminating device, however, the heat dissipation device manufactured by the process has a large weight and has an increased cost due to cost required for machining and surface-treatment, and thus limits the application range of the illuminating device. Further, a heat dissipation device manufactured by a process such as insert molding is used, and manufacture cost of an illuminating device with the heat dissipation device becomes high because of the use of a die casting process during the machining of the heat dissipation device and machining cost in the insert molding.